By right clicking on a virtual machine that's listed in the Virtual PC 2007 console, you can get access to a PROPERTIES dialog. As can be seen here, even though we're running XP in the VM and also have Virtual Machine Additions installed, the properties (where "n/a" is seen) aren't entirely accurate. We were unable to reliably reproduce the problem.
For David Berlind's write-up on The Virtual PC 2007 User Interface, see his post
in ZDNet's TestBed blog.